Color film is widely employed by ameteur and professional photographers for producing movies and color slides. These slides and movies are used in projection devices and the greatly enlarged image thrown on a screen. Color slides may also be reproduced as positive color prints or may be utilized for the production of color separation plates by means of which excellent color reproduction may be obtained by utilizing the color separtion plates in well-known color printing processes.
One of the most popular color films employed is the Kodachrome color film manufactured by the Eastman Kodak Company. This film consists of a film support on which is applied a series of emulsion layers which are responsive or sensitive respectively to the red, green and blue colors in the picture being taken. On development, these colors are transformed to cyan, magneta and yellow. Light beams projected through the developed color film yield the ultimate color of the scene as photographed by the additive effect of the several developed colors as the light beam passes trough the several emulsion layers to the observer.
While the following discussion of the invention referes more particularly to the treatment of color transparency slides it is to be understood that the procedures described for the reduction in color intensity of underexposed Kodachrome color film apply equally to the treatment of underexposed continuous strip movie film. Processing of the latter requires the provision of suitable continuous processing tanks through which the continuous film may be drawn.
As in an photographic process human error or unfavorable light conditions may cause one or more areas of the color film employed to be underexposed or overexposed. Underexposure yields a color transparency exhibiting an undesirable degree of color-intensity with the result that a great deal of the detail in the picture is lost. Overexposure yields a color transparency having a thin, pale and washed-out look. The ability to modify an underexposed color transparency and restore detail to one or more areas by reducing the color intensity using a simple treatment puts a valuable tool into the hands of photographers. A technically unsatisfactory or unsaleable Kodachrome color transparency can be readily transformed into one which exhibits all of the color attributes generally recognized as desirable in the case of color transparencies.